Polymeric compositions



2,998,407 POLRIC COMPOSITIONS Walter E. Foster and Paul E. Koenig, BatonRouge, La.,

assignors to Ethyl Corporation, New York, N .Y., a corporation ofDelaware No Drawing. Filed Dec. 17, 1956, Ser. No. 628,475 9 Claims.(Cl. 26tl46.5)

This invention relates to organic polymers containing tin and othermetallic elements in the chain-building units.

Under normal conditions of use, conventional organic polymers, whereincarbon atoms are the principal repeating units, are sufficiently stablefor most applications. Recently, polymers containing silicon atoms havebeen developed which have the advantage of stability under conditions ofuse more drastic than those for which the organic polymers are intended.However, conditions of use for materials are presently contemplated forwhich no known compositions are suitable. In particular, stability athigh temperature and over wide temperature ranges, high impactresistance, high dielectric strength and exposure to vigorous chemicalattack are increasingly being required in both liquid and solidmaterials employed in numerous articles for commercial or militaryapplications. As a typical example of the rigorous conditions imposed onmaterials are those created during operation of high performanceaircraft where not only are the engine components but also the materialsof construction and exposed surfaces subjected to extremes of conditionsheretofore not encountered.

It is therefore an object of this invention to provide a class ofmaterials susceptible to use in liquid or resinous form having amultitude of uses and highly stable to thermal, electrical, physical andchemical exposure. It is a further object of this invention to providematerials combining the advantageous properties of organic compoundswith the stability characteristic of inorganic compounds. It is likewisean object of this invention to provide processes of manufacturing suchmaterials and methods of formulation and use.

The above and other objects are accomplished by providing organicpolymers characterized by containing structural units containing tinbonded through linking atoms selected from the group consisting ofchalkogen and nitrogen to metallic atoms other than tin capable offorming polyhydroxides Which produce protons in the presence of strongbases.

For purposes of describing the polymers of this invention the followingcharacterization represents one form of such materials.

(SnL), (ML),,

In the above illustrative characterization A, B, C and D compriseorganic radicals, chalkogen or other polymeric units, but at least oneof A, B, C and D is organic; M is a metallic element other than tin,that is, a metal or a metalloid, capable of producing a polyhydroxidewhich in the presence of a sufficiently strong base dissociates to forma proton; L is a chalkogen, that is, oxygen or sulfur, or is trivalentnitrogen; in is the valence of tin, that is, 2 or 4; (a) is zero whenthe valence of the metallic element M is 3 and is 1 when the valence ofthe metallic element M is 4 or 5; and x, y and z are integers.

Among the metallic atoms M, other than tin, forming 2,998,407 PatentedAug. 29, 1961 the polymers of this invention and which are capable offorming polyhydroxides producing protons in the presence of strongbases, the heavy metals, that is, the metals of groups IIIA, IIIB, IV-A,IVB, V-A, V-B, VI-A, VI-B, and VII-B, as Well as the metalloids boron,silicon, phosphorous, arsenic and tellurium are employed.

The foregoing definition of the heavy metals and metalloids is inaccordance with the periodic chart of the elements produced inIntroductory College Chemistry by H. G. Deming, John Wylie and Sons,Inc.

The polymers of this invention are either linear polymers orcross-linked polymers. Cross-linking can occur through the linking atomwhen such atom is nitrogen. Thus while the general class of polymers ofthis invention share in general the properties of high stability tothermal, physical, chemical or electrical forces, the physicalproperties of such polymers are markedly changed when employingchalkogen or unsubstituted nitrogen linking atoms. Furthermore,cross-linking in the polymers can occur through the tin atom or throughthe metallic atom other than tin. When such occurs, as in the graphicrepresentation above, one or more of A, B, C or D can represent otherpolymer units.

In one embodiment of the polymers of this invention the subscripts x andy are 1. In such instances the tin and metallic element M occur inrepeating sequence. However, when the integers x or y are greater than 1the polymers of this invention can contain units wherein either the tincontaining group or metallic element M containing group occurs as arepeating unit as visualized above. In general, it is preferred that theintegers x and y are between 1 and about 200. The molecular Weight ofthe polymers of this invention can vary widely and thus produce avariety of useful materials. In general the integer z can vary from 2 toabout 2000 providing a range of products varying from labile liquids tohard resinous masses.

When the substituents A, B, C and D are organic they can be hydrocarbonor substituted hydrocarbon groups. In general both acyclic and cyclicorganic substituents can be employed. Among the acyclic substituentsaliphatic hydrocarbons having 1 to about 18 carbon atoms are preferredalthough for some purposes such hydrocarbon radicals can contain inertsubstituents such as the halogens. When the organic substituents arecyclic radicals they can be carbocyclic or heterocyclic. Among theheterocyclic radicals it is preferred to employ oxygen, nitrogen orsulfur as the hetero atom. Furthermore, the carbocyclic substituents canbe aliphatic or aromatic. In the heterocyclic embodiment certainunsaturated heterocyclic radicals can be employed and provide highlystable materials. In general it is preferred to employ cyclic radicalshaving between about 4 and 14 carbon atoms in the nucleus. It is to beunderstood that the organic radicals above can be attached to the tin ormetallic elements other than tin or the nitrogen linking atoms eitherdirectly or through a chalkogen, that is, oxygen or sulfur. Theproperties of the resulting polymers are modified thereby. In someinstances, the polymers obtained wherein such organic substituents arelinked through chalkogens exhibit extremely high thermal stability.

When the linking atom L or L employed in the composition of thisinvention is nitrogen and it is desired to obtain polymers notcross-linked at this point in the molecule, the nitrogen atom issubstituted with an organic radical. In general, aliphatic or aromatichydrocarbon radicals are employed for this purpose having 1 to 18 carbonatoms. However, for some purposes heterocyclic radicals having 4 to 6carbon atoms in the nucleus can be employed.

defined class.

Upon further polymerization, or co-polymerization with other organicpolymers of this invention these materials become viscous and, if thetreatment is continued to a high degree of polymerization, are renderedsolid. Many of the liquid polymers of this invention exhibit lowvolatility coupled with high thermal stability. Therefore, suchmaterials find wide application as damping fluids, hydraulic fluids,heat transfer media and lubricant additives. Among the more viscouspolymers of this invention, many exhibit high lubricity and can beemployed as such as or as lubricant additives. Among the solid poly mersof this invention many are thermoplastic and, therefore, can befabricated by extrusion, injection molding and other conventional means.For the preparation of surface coatings having a high degree ofstability under conditions of use, the solid polymers of this inventioncan be dissolved in appropriate solvents, applied to a surface and uponevaporation of the solvent form an adherent permanent coating. In allforms the polymers of this invention are susceptible to pigmentation ordyeing to render the otherwise clear and translucent materials opaque tovisible radiation.

It is not intended from the foregoing discussion to limit the polymersof this invention to tin linked through chalkogen or nitrogen to asingle metallic element of the By appropriate process techniques themetallic elements in the polymers of this invention can comprise aplurality of such elements. This can be achieved by intercondensing thetin-containing reactant with a plurality of metallic compounds or byproducing low molecular weight polymers, of the class defined herein,containing active end groupings, and further condensing such substratesWith similar substrates containing other metals.

In general the polymers of this invention exhibit limited solubility inhydrocarbon solvents and in general somewhat greater solubility insolvents of the coordinating type. Particularly useful among this latterclass are the higher ethers, cyclic ethers and polyethers such asdioxane and the polyethers of polyhydric alcohols.

The physical properties of the compositions of this invention areadditionally dependent upon the tinzmetal ratio. For example, in thecase of a stannosiloxane polymer, when approximately a 1:1 mole ratio ofthe tinzsilicon compounds are employed in the process of this invention,the product is a hard, transparent, glass and relatively insoluble.However, when an excess of the silicon compound is employed, thepolymeric substance is a liquid or a semi-solid. 'For example, when 216parts of diphenylsilanediol are reacted with 288 parts of diphenyltinoxide, the insoluble, hard, transparent glasslike polymeric substanceobtained contains one atom of tin for each atom of silicon. Likewise,when 2160 parts of diphenylsilanediol and 288 parts of diphenyltin oxideare reacted, a liquid, easily soluble polymer substance is obtainedcontaining 10 atoms of silicon for each atom of tin.

One method for manufacturing the polymers of this invention comprisesreacting an organotin oxide with an organo metallic dihydroxide of theappropriate metal as defined hereinabove. In the example which follows,one such process is illustrated wherein the polymer containing tin andsilicon linked through oxygen was prepared. In this and the otherexamples which follow, unless specified otherwise, all parts andpercentages are by weight.

Example I To a reaction vessel provided with means for heating andrefluxing was added a mixture of 216 parts of diphenylsilanediol and 288parts of diphenyltin oxide. After the addition of these reactants,dioxane, 60 percent by weight, was added. Heat was then applied and thereaction mixture refluxed at the atmospheric boiling point for a periodof six hours, during which time the insoluble diphenyltin oxidegradually became dissolved in the dioxane solvent. After the reactionwas complete, as indicated by the substantial disappearance of turbidityof the reaction mixture, the mixture was allowed to cool suflicientlyfor handling and then filtered through a layer of diatomaceous earth.The filtrate containing the product was then distilled at atmosphericpressure so as to remove the greater majority of the dioxane solvent.The last traces of the solvent were then removed by distillation at apressure of 1 mm. of mercury. T he polymeric material having therepeating structure was obtained as a brittle, transparent glass in apercent yield based on the starting materials.

In the foregoing example when the proportions of diphenylsilanediol anddiphenyltin oxide are varied so that an increasing amount ofdiphenylsilanediol is employed, the product varies from the brittlepolymer to a waxy material and to a viscous oil as the amount ofdiphenylsilanediol compound increases.

In addition to the tin-oxygen-silicon polymer produced in the foregoingexample, when the corresponding diols of titanium, vanadium, molybdenum,manganese, aluminum, boron and arsenic are employed in combination withequal molar parts of diphenyltin oxide, similar transparent, solidpolymers are produced having high thermal stability and good dielectricproperties. Similarly, when the diethyl metallo dihydroxide of theforegoing metals are reacted with 4 molar equivalents of dibutyltinoxide, clear, slightly viscous oils are obtained suitable for use ashydraulic fluids having low volatility and a wide liquid temperaturerange. These materials have low toxicity and can be employed insensitive hydraulic systems with out producing corrosion of movingparts.

Another process for producing the polymers of this inventionparticularly applicable where the dihydroxides are diflicultlyobtainable compounds comprises reacting the appropriate diorgano metallodihalide with a diorganotin dialkoxide. In this process alkyl halidesare co-produced and with the higher alkyls provide a convenient reactionmedium for solubilizing the product. For eco- IlOIIllC processes it isusually desirable to recover such alkyl halide by-products for recycle.

Example 11 In a reaction vessel provided with means for heating andrefluxing is placed a mixture of 334 parts of diphenyltin dimethoxide,253 parts of diphenyldichlorosilane, and 1000 parts of diethyleneglycoldimethyl ether. The reaction mixture is heated to reflux; methylchloride is liberated and may be condensed in a cold trap surrounded bysolid carbon dioxide and acetone. After about 36 hours liberation ofmethyl chloride is complete. The reaction ml ture is distilled to removethe solvent. Monomeric contaminants are removed from the polymericresidue by extraction with petroleum ether. The viscous liquid polymericproduct SnO) (Si O} is obtained in satisfactory yields having amolecular weight in the range of 500.

Similarly when the tin reactant is dimethyltin dimethoxide, dibutyltindimethoxide, dicyclohexyltin dimethoxide or methyl phenyltindimethoxide, the co-polymer with the diphenyl dichlorosilane is aviscous liquid or a resinous solid as the proportions of tin to siliconcompound are varied between the limits of 1:1 to 1:10. All such polymershowever have high thermal stability and good dielectric properties.Further, in accordance with the process of Example 11, methyl aluminumsesquichloride, diethyl germanium dibromide, ethyl boron trichloride,and ethyl bismuth diiodide can be condensed in the atom ratio of 1:1with diphenyltin dimethoxide to produce clear, resinous polymers.

Another process for producing the co-polymers of this invention relatedto the foregoing process typified by Example 11 comprises reacting anorgano metallo dihydroxide wherein the metallic element is as definedhereinabove with a diorganotin dichloride in the presence of an alkalimetal. A preferred embodiment of this process, the organo metallic diol,is first reacted with sodium metal in an ether solvent to form thesodium derivative thereof and subsequently react this mixture with thediorganotin dihalide in appropriate proportions to provide polymershaving the desired properties.

Example 111 To a reaction vessel provided with means for agitation,continuous addition of reactants, heating, and refluxing was added 216parts of diphenylsilanediol and 1250 parts of dioxane. To this mixturewas added 46 parts of massive sodium over a period of one hour withvigorous agitation. Upon completion of this addition, during which timethe temperature of the reaction mixture gradually raised to refluxtemperature, refluxing was continued for a period of several hours untilconsumption of the sodium was complete. Thereupon was added 343 parts ofdiphenyltin dichloride dissolved in 2000 parts of dioxane over a periodof one-half hour with vigorous agitation. The reaction mixture was thenrefluxed at atmospheric pressure for a period of one hour. Uponcompletion of the reflux period the mixture was filtered through a layerof diatomaceous earth so as to remove precipitated sodium chloride andother solids, followed by distillation at atmospheric pressure of thefiltrate containing the reaction product so as to remove the solvent. Inorder to remove the last traces of solvent it was necessary to heat thereaction mixture under a pressure of 1 mm. of mercury. The waxypolymeric product having the structure um I was obtained in a 30 percentyield.

The following example illustrates a difierent process useful inmanufacturing the polymers of this invention wherein the organo metallicdihydroxide and the organotin halide are condensed in the properproportions in the presence of a strong base. Among such strong basesare preferred the alkali hydroxides.

Example IV To a reaction flask provided with means for heating,refluxing, continuous addition of reactants and agitation, andcontaining a mixture of 219 parts of dimethyltin dichloride and 364parts of p-phenoxyphenyl-p-t-butylphenylsilanediol and 1000 parts ofchloroform is added 80 parts of sodium hydroxide as a 4 percent aqueoussolution over a period of one-half hour while vigorously stirring thereaction mixture. Upon completion of the addition, the mixture isrefluxed at atmospheric pressure for a period of one hour. The mixtureis then filtered through a layer of diatomaceous earth and the aqueouslayer separated and discarded. Thereafter the chloroform is separatedfrom the product by distillation at atmospheric pressure. The viscoussyrupy polymeric substance having the structure is obtained in goodyield.

In addition to the organo metallo hydroxides in the foregoing examplewhere these are difficultly obtained the corresponding metallo organohalides can be condensed with the organotin dihalide in the presence ofa strong base as shown in the following evample.

Example V The process of Example IV is followed utilizing a mixture of359 parts of isopropyl-Z-naphthyltin dichloride, 253 parts ofdiphenyldichlorosilane, and 1000 parts of dioxane. The waxy polymericsubstance having the structure CH3 CH3 Example VI In this case theprocess of Example I is followed utilizing a mixture of 96 parts ofmethane phosphonic acid and 164 parts of dimethyltin oxide andadditionally employing 500 parts of dioxane. Furthermore, this mixtureis heated for 8 hours at reflux temperature at atmospheric pressure. Theproduct having the structure is obtained in good yield.

Similar polymers are produced by so condensing methane arsonic acid,methane boronic acid, methane bismuth diol and the like with dimethyltinoxide.

Example VII This process employs a mixture of 343 parts of diphenyltindichloride, 104 parts methylaluminum dimethoxide and 500 parts dioxane,following the process of Example II. Additionally, this case varies fromExample II in that a reflux period of 24 hours at atmospheric pressureis employed. However, this process results in more than satisfactoryyields of the white amorphous polymeric substance having the structureWhile the foregoing processes are applicable to the manufacture of theco-polymers of this invention wherein sulfur comprises a linking atom byemploying the sulfur analogs of the materials illustrated above, it isusually more convenient to prepare such sulfur analogs in situ. Thus, ingeneral such polymers can be prepared by reacting the polyfunctionalorgano metallic reactant with hydrogen sulfide in the reaction vesselprior to condensation with the polyfunctional organotin reactant. In apreferred embodiment of this process diorgano metallic dihalides arereacted with hydrogen sulfide and then condensed with a diorganotindihalide. This process is further illustrated in the following example.

Example VIII Following the process of Example III, however in this case.employing as reactants 343 parts of diphenyltin dichloride and 253 partsof diphenylsilane dithiol (prepared in situ by passing hydrogen sulfidethrough a dioxane solution of diphenyldichlorosilane), and utilizing asa solvent a total of 1500 parts of dioxane, satisfactory yields of thesemi solid polymeric product having the structure 2 -SiS S nS \l /..\.lare obtained when the reaction mixture is refluxed at atmosphericpressure for one hour.

Preparation of the polymers of this invention wherein the repeatingunits contain nitrogen is illustrated in the following example whereinthe organo metallic amide is reacted with an organotin compound ofappropriate reactivity. Thus, in general organotin halides and organotinamides are caused to react in the presence of a condensing agent withthe organo metallic amide in monomeric or homo polymeric form. Suchorgano metallic amides of metals other than tin, as hereinabove defined,can in turn be prepared in situ by reaction of the corresponding halideWith ammonia. The resulting polymers are frequently cross-linked throughsuch unsubstituted nitrogen atom to provide materials of high rigidity.If, in place of ammonia in the foregoing reaction, primary amines areemployed the resulting polymer from the reaction of the organo metallicN-amide is largely linear, providing flexible or liquid polymers.

Example IX To a reaction flask provided with means for heating andrefluxing are added 73 parts of octamethylcyclotetra- 8 silazane, 163parts of dimethyltin amide and 500 parts of dioxane. The reactionmixture is refluxed at the atmospheric boiling point for a period of 8hours in the presence of a trace of solid potassium hydroxide. Uponcompletion of the heating period the reaction mixture is filteredthrough a layer of diatomaceous earth and the filtrate containing theproduct is distilled under atmospheric pressure so as to remove thedioxane solvent. The remaining mixture is then subjected to furtherdistillation at a pressure of 1 mm. of mercury removing the last tracesof solvent and leaving as a residue the transparent, resinous polymericproduct having the structure H H (3 a l\ /;3Ha

in substantial yields.

Example X is obtained in satisfactory yields.

Example XI The process of Example IV is followed in this case utilizinga mixture of 244 parts of dimethoxydiphenylsilane, 284 parts ofdibutyltin dimethoxide and 2,000 parts of chloroform, and additionallyadding parts of sodium hydroxide as a 4 percent aqueous solution. Thebrittle transparent polymeric substance having the repeating structure.

6 H laofls'tfh \.1 Leaf is obtained in satisfactory yields.

Example XII In this example the process of Example IV is followed withthe exceptions that 214 parts of diaminodiphenylsilane, 334 parts ofdiphenyltindimethoxide, 1500 parts of chloroform, and furthermore 224parts of potassium hydroxide as a 4 percent solution are used to obtainthe hard, glassy polymeric substance having the repeating structure ZnO-ZiN- \l /..\l l.

in substantial yields.

Example XIII A reaction vessel is equipped with means for heating andrefluxing. To the vessel is added a mixture of 274 parts ofdiphenylstannane, 216 parts of diphenylsilanedoil and 1000 parts ofbenzene. The reaction mixture is then refluxed at atmospheric boilingpoint for a period of one hour. Upon completion of the heating period ofthe reaction mixture is filtered and the aqueous portion of the filtratediscarded. The benzene solvent is then distilled from the reactionmixture at a pressure of .1 mm. of

mercury and the hard, transparent polymeric substance having therepeating structure lieu t9 is obtained in satisfactory yields.

Example XIV The process of Example I is followed, in this case utilizing202 parts of phenylarsonic acid, 164 parts of dimethyltin oxide and 500parts of dioxane so as to obtain the solid, amorphous polymericsubstance having the structure nan In the process of this invention theproportions of reactants employed can be varied within wide limits.However, the properties of the product produced are dependent upon theparticular proportions employed. In general, either reactant can bepresent in major proportions and it is preferred that the ratio ofreactants remain within the limits of 1 to 200:1. The purity of thereactants is important as, to a great degree, the ultimate size of thepolymer produced is dependent upon this factor.

In producing the product of this invention by the various processesdescribed hereinabove, a wide temperature range can be employed. Ingeneral, temperatures varying between about and 400 C. can be employedand within this range it is preferred to operate between about 4 80 and200 C. The upper temperature limit is dependent upon the stability ofthe reactants while the lower temperature limit is chosen so as toprovide a reaction proceeding at a reasonable rate and designed tominimize undesirable side reactions.

The catalyst employed in the process of this invention can be strongacids such as sulfuric acid, hydrochloric acid, nitric acid and thelike. Additionally, the catalyst utilized can be stronge bases, such assodium hydroxide, potassium hydroxide and the like. Furthermore, in someembodiments of this invention, specifically, in those instances where acondensation is effected between an alkoxy metal compound and a tinhalide, it is desirable to employ as a catalyst certain Lewis acids suchas boron trichloride, aluminum trichloride and the like.

The process can be conducted either in a batch or continuous manner. Inbatch operations the total reaction time can be one-half hour to 48hours, however, a half hour to 8 hours is preferred. When carried outcontinuously it is preferred to employ a tube-type reactor. In thelatter case the mixture of metal compounds and tin compounds andadditionally any solvents or catalysts can be fed continuously in thedesired proportions to the inlet end of the tube-type reactor.

We claim:

1. The product obtained by reacting, at reflux temperature in an inertsolvent, (1) a monovalent dihydrocarbon substituted silane, wherein thehydrocarbon group is bonded to the silicon of the silane by carbon tosilicon bonding, and the remaining valences of the silane are directlyconnected to groups from the class consisting of hydroxyl halogen,alkoxy, alkali metallooxy and amine with (2) a tetravalent tin compound,wherein at least two of the valences of the tin are connected directlyto functional groups selected from the class consisting of oxide,hydroxyl, alkoxy, halogen and amine, and the remaining valences of thetin are bonded to at least one monovalent hydrocarbon group by carbon totin bonding, the reaction being carried out under conditions capable ofcausing the silane alone to condense to a material selected from thegroup consisting of siloxanes and silazanes.

2. The product of claim 1 wherein said silane is an aromatic hydrocarbonsilane diol.

3. The product of claim 1 wherein said tin compound is a hydrocarbon tinoxide.

4. The product of claim 1 wherein said silane is an aromaticdihydrocarbon silane diol and said tin compound is a dihydrocarbon tinoxide.

5. The product obtained by reacting, at reflux temperature in an inertsolvent, diphenyl silane diol with diphenyl tin oxide.

6. The product obtained by reacting, at reflux temperature in an inertsolvent, diphenyl dichlorosilane with diphenyl tin dimethoxide.

7. The product obtained by reacting, at reflux temperature in an inertsolvent, dimethoxy diphenyl silane with dibutyl tin dimethoxide, thereaction being conducted in contact with aqueous sodium hydroxide.

8. The product obtained by reacting at reflux temperature in an inertsolvent containing a strong aqueous base (1) a dihydrocarbon silanedihalide wherein the hydrocarbon groups are each monovalent and bondedto the silicon of the silane by carbon-to-silicon bonding, with (2) adihydrocarbon tin dihalide wherein the hydrocarbon groups are eachmonovalent and bonded to the tin by carbon-to-tin bonding.

9. The product obtained by reacting at reflux temperature in an inertsolvent 1) a dialkali metal salt of a dihydrocarbon silane diol whereinthe hydrocarbon groups are each monovalent and bonded to the silicon ofthe silane diol by carbon-to-silicon bonding with (2) a dihydrocarbontin dihalide wherein the hydrocarbon groups are each monovalent andbonded to the tin by carbon-totin bonding.

References Cited in the file of this patent UNITED STATES PATENTS2,413,184 La Lande Dec. 24, 1946 2,713,585 Best July 19, 1955 2,762,821Walde et al Sept. 11, 1956 2,814,601 Currie et a1 Nov. 26, 19572,818,906 Bradley .-..-a Jan. 7, 1958 2,843,555 Berridge July 15, 1958OTHER REFERENCES Danas Textbook of Mineralogy, J. W. Wiley & Sons, Inc.N.Y. (1932), p. 633.

1. THE PRODUCT OBTAINED BY REACTING AT FEFLUX TEMPERATURE IN AN INERTSOLVENT, (1) A MONOVALENT DIHYDROCARBON SUBSTITUTED SILANE, WHEREIN THEHYDROCARBON GROUP IS BONDED TO THE SILICON OF THE SILANE BY CARBON TOSILICON BONDING, AND THE REMAINING VALENCES OF THE SILANE ARE DIRECTLYCONNECTED TO GROUPS FROM THE CLASS CONSISTING OF HYDROXYL HALOGEN,ALKOXY, ALKALI METALLOOXY AND AMINE WITH (2) A TETRAVALENT TIN COMPOUND,WHEREIN AT LEAST TWO OF THE VALENCES OF THE TIN ARE CONNECTED DIRECTLYTO FINTIONAL GROUPS SELECTED FROM THE CLASS CONSISTING OF OXIDE,HYDROXYL, ALKOXY, HALEGEN AND AMINE, AND THE REMAINING VALENCES OF THETIN ARE BONDED TO AT LEAST ONE MONOVALENT HYDROCARBON GROUP BY CARBON TOTIN BONDING, THE REACTION BEING CARRIED OUT UNDER CONDITIONS CAPABLE OFCAUSING THE SILANE ALONE TO CONDENSE TO A MATERIAL SELECTED FROM THEGROUP CONSISTING OF SILOXANES AND SILAZANES.